Strain dependence of antiferromagnetic interface coupling inLa0.7Sr0.3MnO3/SrRuO3superlattices
Strain dependence of antiferromagnetic interface coupling inLa0.7Sr0.3MnO3/SrRuO3superlattices
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DOI：
10.1103/physrevb.91.134405
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发表时间：
2014-11
影响因子：
3.7
通讯作者：
Sujit Das;A. Herklotz;E. Pippel;E. Guo;D. Rata;K. Dorr
中科院分区：
文献类型：
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作者：
Sujit Das;A. Herklotz;E. Pippel;E. Guo;D. Rata;K. Dorr
我们研究了La0.7Sr0.3MnO_3/SrRuO_3超晶格对双轴面内应变的磁响应。在0.72PbMg1/3Nb2/3O3-0.28PbTiO_3(001)(PMN-PT)压电衬底上生长的超晶格显示出两个铁磁成分强烈的反铁磁耦合。在[La0.7Sr0.3MnO_3(22)/SrRuO_3(55)]_(15)超晶格中，在80K可逆双轴应变下，Mu0HAF=2.8T的耦合场减小~-520mT%~-1。这揭示了界面耦合的显著应变效应。施加的面内压缩提高了原始拉伸应变下的锰层的铁磁有序性。因此，应变相关的反铁磁界面耦合和界面附近的Mn-O-Mn铁磁双交换的贡献很难分离，因为Mn自旋的磁序增强导致了更大的界面处SrRuO_3层的净耦合。单离子图像中的应变相关轨道占据不能解释观察到的应变相关的符号，而界面上增强的Mn有序性与之定性一致。
We have investigated the magnetic response of La0.7Sr0.3MnO3/SrRuO3 superlattices to biaxial in-plane strain applied in-situ. Superlattices grown on piezoelectric substrates of 0.72PbMg1/3Nb2/3O3-0.28PbTiO3(001) (PMN-PT) show strong antiferromagnetic coupling of the two ferromagnetic components. The coupling field of mu0HAF = 2.8 T is found to decrease by deltaHAF/delta epsilon ~ -520 mT %-1 under reversible biaxial strain mu0HAF at 80 K in a [La0.7Sr0.3MnO3(22)/SrRuO3(55)]15 superlattice. This reveals a significant strain effect on interfacial coupling. The applied in-plane compression enhances the ferromagnetic order in the manganite layers which are under as-grown tensile strain. It is thus difficult to disentangle the contributions from strain-dependent antiferromagnetic Mn-O-Ru interface coupling and Mn-O-Mn ferromagnetic double exchange near the interface, since the enhanced magnetic order of Mn spins leads to a larger net coupling of SrRuO3 layers at the interface. Strain-dependent orbital occupation in a single-ion picture cannot explain the sign of the observed strain dependence, whereas the enhanced Mn order at the interface is qualitatively in line with it.